git-cl: Use mock.patch instead of custom mock.

Bug: 1051631
Change-Id: I0c8222f89477300e6a14296b72ecaa01d65ca32d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2052627Reviewed-by: Anthony Polito <apolito@google.com>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>

testing_support/auto_stub.py

-# Copyright (c) 2011 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-__version__ = '1.0'
-
-import collections
-import inspect
-import unittest
-
-
-class AutoStubMixIn(object):
-  """Automatically restores stubbed functions on unit test teardDown.
-
-  It's an extremely lightweight mocking class that doesn't require bookeeping.
-  """
-  _saved = None
-
-  def mock(self, obj, member, mock):
-    self._saved = self._saved or collections.OrderedDict()
-    old_value = self._saved.setdefault(
-        obj, collections.OrderedDict()).setdefault(member, getattr(obj, member))
-    setattr(obj, member, mock)
-    return old_value
-
-  def tearDown(self):
-    """Restore all the mocked members."""
-    if self._saved:
-      for obj, items in self._saved.items():
-        for member, previous_value in items.items():
-          setattr(obj, member, previous_value)
-
-
-class SimpleMock(object):
-  """Really simple manual class mock."""
-  def __init__(self, unit_test):
-    """Do not call __init__ if you want to use the global call list to detect
-    ordering across different instances.
-    """
-    self.calls = []
-    self.unit_test = unit_test
-    self.assertEqual = unit_test.assertEqual
-
-  def pop_calls(self):
-    """Returns the list of calls up to date.
-
-    Good to do self.assertEqual(expected, mock.pop_calls()).
-    """
-    calls = self.calls
-    self.calls = []
-    return calls
-
-  def check_calls(self, expected):
-    self.assertEqual(expected, self.pop_calls())
-
-  def _register_call(self, *args, **kwargs):
-    """Registers the name of the caller function."""
-    caller_name = kwargs.pop('caller_name', None) or inspect.stack()[1][3]
-    str_args = ', '.join(repr(arg) for arg in args)
-    str_kwargs = ', '.join('%s=%r' % (k, v) for k, v in kwargs.items())
-    self.calls.append('%s(%s)' % (
-        caller_name, ', '.join(filter(None, [str_args, str_kwargs]))))
-
-
-class TestCase(unittest.TestCase, AutoStubMixIn):
-  """Adds self.mock() and self.has_failed() to a TestCase."""
-  def tearDown(self):
-    AutoStubMixIn.tearDown(self)
-    unittest.TestCase.tearDown(self)
-
-  def has_failed(self):
-    """Returns True if the test has failed."""
-    if not self._resultForDoCleanups:
-      # Maybe skipped.
-      return False
-    return not self._resultForDoCleanups.wasSuccessful()